This invention relates to acetylenic hydroxamic acids which act as inhibitors of TNF-xcex1 converting enzyme (TACE). The compounds of the present invention are useful in disease conditions mediated by TNF-xcex1, such as rheumatoid arthritis, osteoarthritis, sepsis, AIDS, ulcerative colitis, multiple sclerosis, Crohn""s disease and degenerative cartilage loss.
Matrix metalloproteinases (MMPs) are a group of enzymes that have been implicated in the pathological destruction of connective tissue and basement membranes. These zinc containing endopeptidases consist of several subsets of enzymes including collagenases, stromelysins and gelatinases. Of these classes, the gelatinases have been shown to be the MMPs most intimately involved with the growth and spread of tumors. It is known that the level of expression of gelatinase is elevated in malignancies, and that gelatinase can degrade the basement membrane which leads to tumor metastasis. Angiogenesis, required for the growth of solid tumors, has also recently been shown to have a gelatinase component to its pathology. Furthermore, there is evidence to suggest that gelatinase is involved in plaque rupture associated with atherosclerosis. Other conditions mediated by MMPs are restenosis, MMP-mediated osteopenias, inflammatory diseases of the central nervous system, skin aging, tumor growth, osteoarthritis, rheumatoid arthritis, septic arthritis, corneal ulceration, abnormal wound healing, bone disease, proteinuria, aneurysmal aortic disease, degenerative cartilage loss following traumatic joint injury, demyelinating diseases of the nervous system, cirrhosis of the liver, glomerular disease of the kidney, premature rupture of fetal membranes, inflammatory bowel disease, periodontal disease, age related macular degeneration, diabetic retinopathy, proliferative vitreoretinopathy, retinopathy of prematurity, ocular inflammation, keratoconus, Sjogren""s syndrome, myopia, ocular tumors, ocular angiogenesis/neo-vascularization and corneal graft rejection. For recent reviews, see: (1) Recent Advances in Matrix Metalloproteinase Inhibitor Research, R. P. Beckett, A. H. Davidson, A. H. Drummond, P. Huxley and M. Whittaker, Research Focus, Vol. 1, 16-26, (1996), (2) Curr. Opin. Ther. Patents (1994) 4(1): 7-16, (3) Curr. Medicinal Chem. (1995) 2: 743-762, (4) Exp. Opin. Ther. Patents (1995) 5(2): 1087-110, (5) Exp. Opin. Ther. Patents (1995) 5(12): 1287-1196: (6) Exp. Opin. Ther. Patents (1998) 8(3): 281-259.
TNF-xcex1 converting enzyme (TACE) catalyzes the formation of TNF-xcex1 from membrane bound TNF-xcex1 precursor protein. TNF-xcex1 is a pro-inflammatory cytokine that is believed to have a role in rheumatoid arthritis [Shire, M. G.; Muller, G. W. Exp. Opin. Ther. Patents 1998, 8(5), 531; Grossman, J. M.; Brahn, E. J. Women""s Health 1997, 6(6), 627; Isomaki, P.; Punnonen, J. Ann. Med 1997, 29, 499; Camussi, G.; Lupia, E. Drugs, 1998, 55(5), 613.] septic shock [Mathison, et. al. J. Clin. Invest. 1988, 81, 1925; Miethke, et. al. J. Exp. Med. 1992, 175, 91.], graft rejection [Piguet, P. F.; Grau, G. E.; et. al. J. Exp. Med. 1987, 166, 1280.], cachexia [Beutler, B.; Cerami, A. Ann. Rev. Biochem. 1988, 57, 505.], anorexia, inflammation [Ksontini, R,; MacKay, S. L. D.; Moldawer, L. L. Arch. Surg. 1998, 133, 558.], congestive heart failure [Packer, M. Circulation, 1995, 92(6), 1379; Ferrari, R.; Bachetti, T.; et. al. Circulation, 1995, 92(6), 1479.], post-ischaemic reperfusion injury, inflammatory disease of the central nervous system, inflammatory bowel disease, insulin resistance [Hotamisligil, G. S.; Shargill, N. S.; Spiegelman, B. M.; et. al. Science, 1993, 259, 87.] and HIV infection [Peterson, P. K.; Gekker, G.; et. al. J. Clin. Invest. 1992, 89, 574; Pallares-Trujillo, J.; Lopez-Soriano, F. J. Argiles, J. M. Med. Res. Reviews, 1995, 15(6), 533.]], in addition to its well-documented antitumor properties [Old, L. Science, 1985, 230, 630.]. For example, research with anti-TNFxcex1 antibodies and transgenic animals has demonstrated that blocking the formation of TNF-xcex1 inhibits the progression of arthritis [Rankin, E. C.; Choy, E. H.; Kassimos, D.; Kingsley, G. H.; Sopwith, A. M.; Isenberg, D. A.; Panayi, G. S. Br. J. Rheumatol. 1995, 34, 334; Pharmaprojects, 1996, Therapeutic Updates 17 (Oct.), au197-M2Z.]. This observation has recently been extended to humans as well as described in xe2x80x9cTNF-xcex1 in Human Diseasesxe2x80x9d, Current Pharmaceutical Design, 1996, 2, 662.
It is expected that small molecule inhibitors of TACE win have the potential for treating a variety of disease states. Although a variety of TACE inhibitors are known, many of these molecules are peptidic and peptide-like which suffer from bioavailability and pharmacokinetic problems. In addition, many of these molecules are non-selective, being potent inhibitors of matrix metalloproteinases and, in particular, MMP-1. Inhibition of MMP-l (collagenase 1) has been postulated to cause joint pain in clinical trials of MMP inhibitors [Scrip, 1998, 2349, 20] Long acting, selective, orally bioavailable non-peptide inhibitors of TACE would thus be highly desirable for the treatment of the disease states discussed above.
Sulfone hydroxamic acid inhibitors of MMPs, of general structure I have been disclosed [Burgess, L. E.; Rizzi, J. P.; Rawson, D. J. Eur Patent Appl. 818442. Groneberg, R. D.; Neuenschwander, K. W.; Djuric, S. W.; McGeehan, G. M.; Burns, C. J.; Condon, S. M.; Morrissette, M. M.; Salvino, J. M.; Scotese, A. C.; Ullrich, J. W. PCT Int. Appl. WO 97/24117. Bender, S. L.; Broka, C. A.; Campbell, J. A.; Castelhano, A. L.; Fisher, L. E.; Hendricks, R. T.; Sarma, K. Eur. Patent Appl. 780386. Venkatesan, A. M.; Grosu, G. T.; Davis, J. M.; Hu, B.; O""Dell, M. J. PCT Int. Appl. WO 98/38163.]. An exemplification of this class of MMP inhibitor is RS-130830, shown below. 
Within the sulfone-hydroxamic acid class of MMP inhibitor, the linker between the sulfone and hydroxamic acid moieties has been extended to three carbons (I, n=2) without significant loss in potency [Barta, T. E.; Becker, D. P.; Villamil, C. I.; Freskos, J. N.; Mischke, B. V.; Mullins, P. B.; Heintz, R. M.; Getman, D. P.; McDonald, J. J. PCT Int. Appl. WO 98/39316. McDonald, J. J.; Barta, T. E.; Becker, D. P.; Bedell, L. J.; Rao, S. N.; Freskos, J. N.; Mischke, B. V. PCT Int. Appl. WO 98/38859.].
Piperidine sulfone hydroxamic acids, II (n=1) have been reported [Becker, D. P.; Villamil, C. I.; Boehm, T. L.; Getman, D. P.; McDonald, J. J.; DeCrescenzo, G. A. PCT Int. Appl. WO 98/39315.]. Similar piperidine derivatives in which the methylene linking the piperidine ring to the sulfone has been deleted (II, n=0) have been reported [Venkatesan, A. M.; Grosu, G. T.; Davis, J. M.; Baker, J. L. PCT Int. Appl. WO 98/37877.]. 
Sulfone-hydroxamic acids III, in which a hydroxyl group has been placed alpha to the hydroxamic acid, have been disclosed [Freskos, J. N.; Boehm, T. L.; Mischke, B. V.; Heintz, R. M.; McDonald, J. J.; DeCrescenzo, G. A.; Howard, S. C. PCT Int. Appl. WO 98/39326. Robinson, R. P. PCT Int. Appl. WO 98/34915.]. 
Sulfone-based MMP inhibitors of general structure IV, which utilize a thiol as the zinc chelator, have been reported [Freskos, J. N.; Abbas, Z. S.; DeCrescenzo, G. A.; Getman, D. P.; Heintz, R. M.; Mischke, B. V.; McDonald, J. J. PCT Int. Appl. WO 98/03164]. 
Inhibitors of stromelysin with general structure V have been disclosed [Shuker, S. B.; Hajduk, P. J.; Meadows, R. P.; Fesik, S. W. Science, 1996, 274, 1531-1534. Hajduk, P. J.; Sheppard, G.; Nettesheim, D. G.; Olejniczak, E. T.; Shuker, S. B.; Meadows, R. P.; Steinman, D. H.; Carrera, Jr., G. M.; Marcotte, P. A.; Severin, J.;
Walter, K.; Smith, H.; Gubbins, E.; Simmer, R.; Holzman, T. F.; Morgan, D. W.;
Davidsen, S. K.; Summers, J. B.; Fesik, S. W. J. Am. Chem. Soc. 1997, 119, 5818-5827. Olejiniczak, E. T.; Hajduk, P. J.; Marcotte, P. A.; Nettesheim, D. G.; Meadows, R. P.; Edalji, R.; Holzman, T. F.; Fesik, S. W. J. Am. Chem. Soc. 1997, 119, 5828-5832. Fesik, S. W.; Summers, J. B.; Davidsen, S. K.; Sheppard, G. S.; Steinman, D. H.; Carrera, G. M.; Florjancic, A.; Holms, J. H. PCT Int. Appl. WO 97/18188.]. 
Salah et al., Liebigs Ann. Chem. 195, (1973) discloses some aryl substituted thio and aryl substituted sulfonyl acetohydroxamic acid derivatives of general formula 1. These compounds were prepared to study the Mannich reaction. Subsequently, they were tested for their fungicidal activity. 
Some sulfone carboxylic acids are disclosed in U.S. Pat. No. 4,933,367. Those compounds were shown to exhibit hypoglycemic activity.